This application claims benefit of Japanese Patent Application No. 2001-382132 filed on Dec. 14, 2001, the contents of which are incorporated by the reference.
The present invention relates to key input devices and portable terminal input devices and, more particularly, to key input devices and portable terminal input devices, for which it is demanded to reduce size and improve key input operation property as in portable terminals.
CPUs (central processing units) use switches for their operation. To start the operation of microscopic circuits of the CPU, macroscopic mechanical switches are necessary. Switches which prescribe the operational conditions of PCs (personal computers) are usually referred to as keys. A key board is provided to the PC in a steady-state fashion. The number of keys provided in the keyboard is the sum of the number of alphabet letter keys, the number of function keys, the number of numeral keys and the number of other additional function keys. This sum is more than 100. For key-less operation of the CPU, a key called mouse is used.
In portable telephone sets, such a number of keys can not be practically disposed. Not only for portable telephone sets but also for many other electronic devices, it is demanded to reduce the number of keys prescribing the operation start condition of their CPU. Particularly, for portable electronic devices for which size reduction is demanded, not only the key number reduction but also the physical size reduction of keys is demanded. From the standpoints of practical merits and usefulness, such size reduction should not result in deterioration of the mechanical and physical performance of the mechanical switches. As for the mechanical and physical performance, both the reliability of switching function and the reliable transmission of operation sense such as that called click sense.
As switch having these two different kinds of performance, a sheet switch is well known in the art, in which a group of switches is formed in a sheet-like arrangement. The sheet switch is excellent in its displacing and restoring properties. FIGS. 13(a) to 13(c) show a unit switch or unit key (or key element), which is reduced in size but is excellent in the two different kinds of performance. This unit switch is called dome-like switch. As shown in FIG. 13(a), this well-known unit key has two electrodes, i.e., an annular thin film electrode 101 and a dot-like thin film electrode 102. The annular and dot-like thin film electrodes 101 and 102 are both formed on an electrode substrate (not shown) having a multiple sub-layer wiring layer. The annular and dot-like thin film electrodes 101 and 102 are connected to lead lines of wiring, which is formed three-dimensionally inside the multiple sub-layer wiring layer. FIG. 13(c) shows a movable switching element. This switching element is formed as a semi-spherical shell-like thin metal sheet member 103. In lieu of the thin metal sheet member 103, it is possible to use a semi-spherical shell-like elastomer resin member, which has an electrically conductive film bonded to its inner surface. In FIG. 13(c), the thin metal sheet member 103 is shown such that its top part has been pushed down. As a result of pushing down the top part, the inner surface thereof is brought into contact with the dot-like thin film electrode 102, and an equivalent switching circuit 104 as shown in FIG. 14 is turned on.
In the well-known dome-like switch, which is excellent in the two different kinds of performance as noted above, i.e., the reliability of switching function and an transmission of operation sense. One operation made manually corresponds to one electronic switching operation. Such one-to-one correspondence is excellent in regard of mechanical relay function between person and CPU. It is demanded to reduce the key number by one-to-plurality correspondence while preserving the excellent mechanical relay function between man and CPU.
As switch which is capable of executing a plurality of switching functions by selecting a plurality of positions in response to one manual operation owing to one-to-plurality correspondence, many switches having different mechanical structures are well known in the art as shown in, for instance, Japanese Utility Model Laid-Open No. 7-16339, Japanese Patent Laid-Open No. 7-262865, Japanese Patent Laid-Open No. 2001-56730 and Japanese Patent Laid-Open No. 10-49295. In portable telephone set PCs having a switch group formed by a number of witch elements, it is demanded that the individual switch elements are formed in small size and reliably operable, it is essentially demanded to reduce the area necessary for the circuit structure including the switches, and it is further demanded that instantaneous operation is possible. Particularly, it is thought to be important that reliable transmission of operation sense, permitting confirmation of switching operation during the operation of depressing a switch, is realized.
The present invention has an object of providing an input device and a portable terminal input device, in which excellent mechanical relay function between person and CPU is preserved, many small key elements are disposed collectively as a group, reliable property of operation sense transmission permitting confirmation of switching operation is realized, and consequently it is possible to reduce the number of keys owing to one-to-plurality correspondence.
Means for attaining the above object are expressed as follows. To technical items in the expression are annexed numerals, symbols, etc. in parenthesis. These numerals, symbols, etc. are identical with reference numerals, symbols, etc. attached to technical items in a plurality of embodiments or one or more embodiments there among according to the present invention, particularly to technical items expressed in the embodiments or drawings corresponding thereto. Such reference numerals, symbols, etc. clarify the correspondence or mediation between technical items set forth in claims and technical items in the embodiments. Such correspondence or mediation does not mean that the technical items as set forth in claims are to be interpreted as being limited to the technical items in the embodiments.
A key input device according to the present invention comprises a wiring substrate (2); and a plurality of keys (1) disposed on the wiring substrate (2) and each having three-dimensional displacement surfaces capable of being displaced in a linked fashion relative to one another. The three-dimensional displacement surfaces comprises a preceding displacement surface capable of undergoing a first displacement preceding in time; and a succeeding displacement surface capable of undergoing a second displacement subsequent in time to the first displacement of the preceding displacement surface. The succeeding displacement surface is capable of undergoing the second displacement by a displacing force of the first displacement. The plurality of keys (1) each have a first key (3) forming the preceding displacement surface; and a second key (4) having the succeeding displacement surface. A first switching operation is brought about when a first key (1) part of the first key (1) and a first substrate part (12, 43) of the wiring substrate are brought into mechanical contact with each other on the basis of displacement of the preceding displacement surface. A second switching operation is brought about when a second key part of the second key (4) and a second substrate part (13, 46) of the wiring substrate (2) are brought into mechanical contact with each other on the basis of displacement of the succeeding displacement surface. Each of the keys (1) executes the first and second switching operations by movement of its part perpendicular to the substrate (2) surface of the wiring substrate.
It is particularly important that the preceding and succeeding displacement surfaces both form, before displacement, surfaces convex in a direction opposite to the direction of movement. A change from convex surface before displacement to concave surface after displacement, physically means that an upper dead center is present during the progress of displacement. At the time of passing the upper dead center, reliable transmission of an operation sense permitting confirmation of a switching operation can be reliably obtained in view of sense. Consequently, a plurality of steps of click senses are obtained in a linked fashion, while the number of keys 5 can be reduced. The number of steps is not limited to two, but a triple-wall dome-like form permits three-step click sense to be obtained in a linked fashion.
A single key has two operating surfaces, i.e., a preceding and a succeeding displacement surface, and when it receives a single external force exerted in a single direction, it can execute two switching operations self-matchingly and in a linked fashion. Such a key structure is capable of making a double action although it is actually a single switch, thus actually permitting the reduction of the number of switches or keys to one half and also permitting manual operation speed increase. One key can serve as two keys and is operable as one function key.
The common attaining means described above for realizing the double action, is realized by the following two attaining means. The first and second keys (3) and (4) are geometrically related one outside the other. In a first attaining means, the first and second keys (3) and (4) are spaced apart in a direction perpendicular to the substrate surface of the wiring substrate (2), and the first key (3) is disposed outside the second key (4) with respect to the wiring substrate surface. In a special case, the second key (4) is found in a closed space defined by the first key (3) and the wiring substrate (2). In a second attaining means, the first and second keys (3) and (4) are spaced apart in a direction parallel to the substrate surface of the wiring substrate (2). The second key (2) is enclosed in the first key (3), and is disposed to be continuous to and connected to the inner side of the first key (3). The first and second keys (3) and (4) and the wiring substrate (2) form a single closed space.
The first switching operation is brought about when the first key part and the first substrate part (12) of the wiring substrate (2) are brought into contact via the second key part with each other. The first key (3), the wiring substrate (2) and the second key (4) together form a first closed space. The second key (4) and the wiring substrate (2) together form a second closed space. The second key (4) is within a third space formed by the first key (3) and the wiring substrate (2). As shown, the first key (3) causes displacement and deformation of the second key (4) in the third closed space.
The wiring substrate (2) has a first electrode (12) fixedly bonded to the first key (3), a second electrode (13) fixedly bonded to the second key (4), and a third electrode (14) facing the second closed space. The first substrate part (13) corresponds to the second electrode (13) and the second substrate part (14) corresponds to the third electrode. The first electrode (12) forms a first closed ring, and the second electrode (13) forms a second closed ring. The first key (3) has its entire circumference bonded to the first ring, the second key (4) has its entire circumference bonded to the second ring, the first ring is electrically connected to GND (23), the second ring is connected to a first input port (24) of a CPU (central processing unit), and the third electrode (14) is connected to a second input port (25) of the CPU. With the double action, the CPU is operable in two different ways.
Here, the first key (3) has an electrically conductive first inner surface, the first inner surface is electrically connected to the first electrode (12), the second key (4) has an electrically conductive second inner surface, and the second inner surface is electrically connected to the second electrode (13). This is clearly understandable from the circuit construction even without any clear description. The inventive step is not given by the above, but is merely mentioned for the description.
The first key (3) has a first body part made of a resin and a first electrically conductive film formed on the inner side of the first body part. The first inner surface corresponds to the inner surface of the first electrically conductive film (not shown) . The second key (4) has a second body part made of a resin and a second electrically conductive film (not shown) formed on the inner side of the second body part. The second inner surface corresponding to the inner surface of the second electrically conductive film. Such multiple layer key structure is practically useful in view of both the electric conductivity and the flexible deformation property. As copper alloy thin films and aluminum alloy thin films, those which can widthstand 10,000,000 times of folding have been developed and practically useful. On the other hand, a multiple layer structure constituted by resin and electrically conductive films is excellent in the mass production property. It is possible to form keys from the sole electrically conductive resin. In the case of using resin, it is possible to assemble together keys and wiring substrate close-contact-wise and high and mass production manners by insert injection molding techniques.
The wiring substrate (2) has a plurality of lead lines formed in its inside and either one of the first to third electrodes is electrically connected via a connecting lead (17) extending perpendicular to the wiring substrate to the wiring. The more the number of function keys, the higher effect of reducing the circuit area with the multiple layer wiring substrate is obtainable.
The first and second keys (3), (4) are both especially preferably semi-spherical shell-like in form. While the key movement direction may be a single direction, since the key is semi-spherical shell-like in form, the single direction can freely follow the direction of push-down of a man""s finger. The first and second keys (3), (4) are both frust-conical in form. Generally, it is important to provide a dome-like form like the well-known dome-like switch.
The preceding and succeeding displacement surfaces form a continuous displacement surface, and the continuous displacement surface and the substrate (2) surface of the wiring substrate form a single closed space. The wiring substrate (2) has a first lead line having a first disconnected part (43), and a second lead line having a second disconnected part (46). The first and second key parts (35), (37) are both electrically conductive, the first switching operation is brought about when the first key part (35) is electrically coupled to the first disconnected part (43, 44, 45), and the second switching operation is brought about when the second key part (37) is electrically coupled to the second disconnected part (46, 47, 48). The first lead line has one side (44) electrically connected to the ground (23) and the other side (45) connected to the first input port (25) of the CPU, and the second lead line (47) has one side (48) electrically connected to the ground (23) and the other side (47) connected to the second input port (24) of the CPU. The first key (3) has a first frust-conical form part (31) having a larger outer diameter and a first disk-like part (32) integral with the first frust-conical form part (31) and substantially parallel to the wiring substrate surface. The second key (4) has a second frust-conical form part (33) having a smaller outer diameter and a second disk-like part (34) integral with the second frust-conical form part (33) and substantially parallel to the wiring substrate surface. The first disk-like part (32) is integral with the second frust-conical form part (33). The first key part (35) is formed on the first disk-like part (32), and the second key part (37) is formed on the second disk-like part (32).
More specifically, the first key (3) has a first partly spherical shell-like part (51) having a larger outer diameter and a second partly spherical shell-like part (52) having a smaller outer diameter. The first partly spherical shell-like part (51) is continuous to and integral with the second partly spherical shell-like part (52). The first lead line has a first one side disconnected part (44) formed in a first one side concave part and also has a first other side disconnected part (45) formed in a first other side concave part. The first one side disconnected part (44) has a portion extending in the first other side concave part, and the first other side disconnected part having a portion extending in the first one side concave part. The second lead line has a second one side disconnected part (48) formed in a second one side concave part and also has a second other side disconnected part (47) formed in a second other side concave part. The second one side disconnected part (48) having a portion extending in the second one side disconnected part, and the second other sided is connected part (47) having a portion extending in the second one side concave part. Such a structure makes reliable electrical connection. The surfaces (36), (38) of the first and second key parts (35), (37) are both preferably smoothly curved surfaces.
The input device for a portable terminal according to the present invention comprises a casing (not shown), a CPU keyboard (not shown) disposed within the casing and having a CPU, a key group movably supported on the casing and constituted by a plurality of keys (1) formed as elements on the outer surface of the casing, and a wiring substrate (2) having a plurality of electrodes supported on the casing such as to be capable of being contacted by the keys (1). The movement of each key (1) is a reciprocal movement having components in a perpendicular direction to the outer surface. The key (1) is brought into contact with electrodes (13 and 14, or 47 and 46) by two-step contact in a forward stroke in the perpendicular direction. The second contact in the two-step contact is a mechanically essential condition for the first contact of the two-step contact. The two-step contact switches the voltage states of the two input ports of the CPU in a linked fashion.
The electric two-step contact of the double action, permits reducing the input device of the portable terminal device, increasing the speed of the input operation and smoother input operation of highly functional digital portable telephone sets that will appear in the future. More specifically, the first step contact corresponds to numeral xe2x80x9cjxe2x80x9d of a numeral key, and the second step contact corresponds to numeral xe2x80x9cj+1xe2x80x9d of the numeral key. If the minimum value of the numeral xe2x80x9cjxe2x80x9d is xe2x80x9c0xe2x80x9d, the second step contact corresponds to an odd numeral of the numeral key. There are many program start linked functions of starting one operation by inputting two electric signals to the CPU. In such case, the user can start the program with a single action.
The keys (1) each have a first function key, a second function key, shallow push-down of the first function key causes start of a function fxc2x71, shallow push-down of the second function key causes start of a function fxc2x72, and deep push-down of the first function key causes start of a function fxc2x73 corresponding to the shallow push-down of the first function key and the shallow push-down of the second function key. The operations of these linked fashion are made fast.